Temporal trends in neonatal outcomes following iatrogenic preterm delivery

<p>Abstract</p> <p>Background</p> <p>Preterm birth rates have increased substantially in the recent years mostly due to obstetric intervention. We studied the effects of increasing iatrogenic preterm birth on temporal trends in perinatal mortality and serious neonatal morbidity in the United States.</p> <p>Methods</p> <p>We used data on singleton and twin births in the United States, 1995-2005 (n = 36,399,333), to examine trends in stillbirths, neonatal deaths, and serious neonatal morbidity (5-minute Apgar ≤3, assisted ventilation ≥30 min and neonatal seizures). Preterm birth subtypes were identified using an algorithm that categorized live births <37 weeks into iatrogenic preterm births, births following premature rupture of membranes and spontaneous preterm births. Temporal changes were quantified using odds ratios (OR) and 95% confidence intervals (CI).</p> <p>Results</p> <p>Among singletons, preterm birth increased from 7.3 to 8.8 per 100 live births from 1995 to 2005, while iatrogenic preterm birth increased from 2.2 to 3.7 per 100 live births. Stillbirth rates declined from 3.4 to 3.0 per 1,000 total births from 1995-96 to 2004-05, and neonatal mortality rates declined from 2.4 to 2.1 per 1,000 live births. Temporal declines in neonatal mortality/morbidity were most pronounced at 34-36 weeks gestation and larger among iatrogenic preterm births (OR = 0.75, CI 0.73-0.77) than among spontaneous preterm births (OR = 0.82, CI 0.80-0.84); P < 0.001. Similar patterns were observed among twins, with some notable differences.</p> <p>Conclusion</p> <p>Increases in iatrogenic preterm birth have been accompanied by declines in perinatal mortality. The temporal decline in neonatal mortality/serious neonatal morbidity has been larger among iatrogenic preterm births as compared with spontaneous preterm births.</p

Smooth values of polynomials

Given $f\in \mathbb{Z}[t]$ of positive degree, we investigate the existence of auxiliary polynomials $g\in \mathbb{Z}[t]$ for which $f(g(t))$ factors as a product of polynomials of small relative degree. One consequence of this work shows that for any quadratic polynomial $f\in\mathbb{Z}[t]$ and any $\epsilon > 0$, there are infinitely many $n\in\mathbb{N}$ for which the largest prime factor of $f(n)$ is no larger than $n^{\epsilon}$

Influence of definition based versus pragmatic birth registration on international comparisons of perinatal and infant mortality: population based retrospective study

Objectives To examine variations in the registration of extremely low birthweight and early gestation births and to assess their effect on perinatal and infant mortality rankings of industrialised countries

Atonic Postpartum Hemorrhage: Blood Loss, Risk Factors, and Third Stage Management

AbstractObjectiveAtonic postpartum hemorrhage rates have increased in many industrialized countries in recent years. We examined the blood loss, risk factors, and management of the third stage of labour associated with atonic postpartum hemorrhage.MethodsWe carried out a case-control study of patients in eight tertiary care hospitals in Canada between January 2011 and December 2013. Cases were defined as women with a diagnosis of atonic postpartum hemorrhage, and controls (without postpartum hemorrhage) were matched with cases by hospital and date of delivery. Estimated blood loss, risk factors, and management of the third stage labour were compared between cases and controls. Conditional logistic regression was used to adjust for confounding.ResultsThe study included 383 cases and 383 controls. Cases had significantly higher mean estimated blood loss than controls. However, 16.7% of cases who delivered vaginally and 34.1% of cases who delivered by Caesarean section (CS) had a blood loss of < 500 mL and < 1000 mL, respectively; 8.2% of controls who delivered vaginally and 6.7% of controls who delivered by CS had blood loss consistent with a diagnosis of postpartum hemorrhage. Factors associated with atonic postpartum hemorrhage included known protective factors (e.g., delivery by CS) and risk factors (e.g., nulliparity, vaginal birth after CS). Uterotonic use was more common in cases than in controls (97.6% vs. 92.9%, P < 0.001). Delayed cord clamping was only used among those who delivered vaginally (7.7% cases vs. 14.6% controls, P = 0.06).ConclusionThere is substantial misclassification in the diagnosis of atonic postpartum hemorrhage, and this could potentially explain the observed temporal increase in postpartum hemorrhage rates

Vulnerable newborn types: Analysis of population-based registries for 165 million births in 23 countries, 2000-2021.

OBJECTIVE: To examine the prevalence of novel newborn types among 165 million live births in 23 countries from 2000 to 2021. DESIGN: Population-based, multi-country analysis. SETTING: National data systems in 23 middle- and high-income countries. POPULATION: Liveborn infants. METHODS: Country teams with high-quality data were invited to be part of the Vulnerable Newborn Measurement Collaboration. We classified live births by six newborn types based on gestational age information (preterm 90th centile) for gestational age, according to INTERGROWTH-21st standards. We considered small newborn types of any combination of preterm or SGA, and term + LGA was considered large. Time trends were analysed using 3-year moving averages for small and large types. MAIN OUTCOME MEASURES: Prevalence of six newborn types. RESULTS: We analysed 165 017 419 live births and the median prevalence of small types was 11.7% - highest in Malaysia (26%) and Qatar (15.7%). Overall, 18.1% of newborns were large (term + LGA) and was highest in Estonia 28.8% and Denmark 25.9%. Time trends of small and large infants were relatively stable in most countries. CONCLUSIONS: The distribution of newborn types varies across the 23 middle- and high-income countries. Small newborn types were highest in west Asian countries and large types were highest in Europe. To better understand the global patterns of these novel newborn types, more information is needed, especially from low- and middle-income countries

Impact of delayed childbearing in BC, Canada

This thesis examines the association between maternal age and adverse birth outcomes in the province of British Columbia (Canada). It explores the differential effect of plurality and parity on this association; and describes differences in obstetric interventions and birth outcomes between older mothers living in rural versus urban areas. Data were obtained from the BC Perinatal Health Program’s Database Registry, 1999-2003. The database includes all births in BC and contains information about maternal demographic characteristics, behavioural and life-style factors, and obstetric history. Among older mothers with singleton pregnancies, we observed a higher rate of stillbirths, preterm births, small-for-gestational-age babies, and admissions to a neonatal intensive care. The risk of preterm birth and small-for-gestational-age was modified by parity. The relative risk of preterm birth associated with maternal age was higher among primiparae, compared to multiparae. Older primiparae were at elevated risk for SGA; no such association was found among multiparae. In twin pregnancies, maternal age was not associated with perinatal death, very preterm birth, small-for-gestational-age, or prolonged neonatal intensive care unit admissions (13 days or longer), regardless of parity. However, the results suggest that the risk of these adverse outcomes is lower among older compared to younger primiparae. Chorionicity did not explain these results. Older mothers living in rural versus urban areas had lower rates of caesarean sections and higher rates of perinatal death; the risk of small-for-gestation-age was lower, whereas large-for-gestational-age was higher. The rates of labour induction, emergency caesarean-section, preterm birth, and NICU admission were similar in both groups. The risk of caesarean-section and perinatal death increased with the distance from the mother’s residence to the nearest hospital with caesarean -section capacity. This research adds to current knowledge by demonstrating a differential effect of parity on the association between maternal age and preterm birth and small-for-gestational-age among singletons. This is the first population-based study of twins to explore the effect of parity on the association between maternal age and birth outcomes other that preterm birth. In addition, this is the first study to examine the effect of rural or remote residence on birth outcomes among older mothers.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat